Traverse mechanism



Aug. 16, 1966 BRlsCOE 3,266,740

TRAVERSE MECHANISM Filed May 25, 1964 5 Sheets$heet l HG. I

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' TRAVERSE MECHANISM Filed May 25, 1964 5 Sheets-Sheet 2 F I G. 2

6, 1966 J. A. BRISCOE 3,266,740

TRAVERSE MEGHANI SM Filed May 25, 1964 5 Sheets-Sheet 5 4? rr ms United States Patent 3,266,740, TRAVERSE MECHANISM Josiah Alfred Briscoe, Harrogate, England, assignor to Imperial Chemical industries Limited, London, England, a corporation of Great Britain Filed May 25, 1964, Ser. No. 370,022 Claims priority, application Great Britain, Sept. 17, 1963, 36,534/63 3 Claims. (Cl. 24243) This invention relates to textile winding machines, in particular to a traverse device for the high speed winding of yarn.

In the high speed winding of yarns, particularly the winding of continuous filament yarns formed from synthetic thermoplastic polymers 'by melt spinning, cylindrical yarn packages having flat ends, sometimes referred to as cheeses, are frequently required and these are produced by winding the yarn onto a cylindrical bobbin. With this form of winding it has been found that the ends of the package are self-supporting only if the helix angle of lay of the yarn is maintained at about The yarn is laid on the rotating bobbin by means of a guide, situated close to the bobbin surface, which reciprocates back and forth in a path substantially parallel to the bobbin surface and somewhat shorter than the bobbin length. To maintain the 5 helix angle the linear speed of the yarn guide must be about one tenth of the winding speed; furthermore the guide must reverse its direction of travel as rapidly as possible at each end of the traverse path in order to avoid hard ends to the package or the formation of loops of yarn which will drop away from the ends of the package. Traverse mechanisms capable of operation at speeds up to about 5000 feet per minute are known but modern processing developments, especially of synthetic fibres, are demanding increasingly high winding speeds of the order of 20,000 feet per minute or more.

Such high winding speeds require traverse mechanisms capable of continuous operation at proportionately high speeds and it is one object of the present invention to provide a traverse device which will operate continuously at high speeds while still maintaining the necessary helix angle of lay of the yarn.

Thus according to the present invention We provide a traverse device for the high speed winding of yarns characterized in that the device consists of primary and secondary traverse mechanisms, the former comprising two oppositely placed, rotating cams, each formed from the frustum of a hollow cone and the latter is a carriage bearing the primary traverse mechanism, arranged to move to and fro along a traverse path in at least two steps in each direction.

The profiles of the cams of the primary traverse mechanism are formed by cutting away the sides of each conical frustum to make a profile having at least one, preferably two, troughs and a corresponding number of peaks within the perimeter of the cam. The cams are preferably balanced to facilitate high speed rotation. Cams having more than two peaks (and troughs) may be used but as the number increases above two the size of the cam, for a particular traverse length, also increases and may be come inconveniently large.

In operation the yarn is guided between the two oppositely placed cams and alternately contacts each profile. As the cams, which are positioned close to the wind up bobbin, rotate the yarn is translated from side to side and laid on a length of the bobbin corresponding to one step of the motion of the secondary traverse mechanism.

In order that the invention may be more readily understood reference is made to the accompanying drawings which illustrate diagrammatically and by way of example "ice one embodiment of the traverse device of the present invention, wherein:

FIGURE 1 is a top plan view of a traverse device,

FIGURE 2 is an enlarged view of part of FIGURE 1 showing the front view of a primary traverse mechanism, part sectioned, and its relationship to the wind-up bobbin.

FIGURE 3 shows the profiles of the two cams comprising the primary traverse mechanisms.

Referring now to FIGURE 1, two conical cams, 1 and 2, are connected by a common flexible shaft 3, which extends through each cam and runs in bearings 4 and 5, the whole primary traverse mechanism being mounted on carriage, 6, of the secondary traverse mechanism by means of supporting brackets 7. The cams, 1 and 2, are rotated by a common driving means (not shown). The carriage 6 is mounted for movement in a horizontal plane on a pair of rails 8 which are attached to a main framework 9. A main shaft 15 is mounted at its ends on the main framework 9 in bearings 16 and is rotated during operation by any suitable means (not shown). The shaft 15 carries a series of discs which are fixed to the shaft and which are axially spaced apart to define a plurality of spaces 11. Each of the discs intermediate the end discs is provided with longitudinal grooves 12, 13 14 in its periphery. A pin 10 fixed to the carriage 6 is engageable with the spaces 11 and with the longitudinal grooves 12, 13, 14. A double acting cylinder 17 with a piston operated by fluid pressure is mounted on the main framework 9 and a piston rod 18 is connected to the carriage 6. A lever 19 is pivotally mounted at one end of the carriage (a replica 20 being mounted at the other end of the carriage) which engages with a pin 21 on the periphery of one of the end discs on the shaft 15. This lever, when moved by the pin 21, operates valve 22 which releases the pressure from one end of the cylinder 17 and applies pressure to the other end of the cylinder. Likewise at the end of the return stroke the pin 13a on the other end disc engages a lever 20 and again reverses the pressure through valve 22. Following each reversal the lever 19 or 20 moves to the angular position of the lever 20 as shown in FIGURE 1. This movement may be effected in any suitable manner as by the provision of stops (not shown) on each end of the main framework 9 or by the action of springs (not shown) within the valve 22, the springs being arranged to bias the valve arms 31 and 32 outwardly.

Before describing the operation of the traverse device of FIGURE 1, reference is made to FIGURE 2, wherein the details of construction of the primary traverse mechanism are illustrated.

The conical cams 1 and 2, each of which includes a stub shaft 3 mounted in one of the bearings 4 or 5, are connected by the flexible shaft 3. The axes of rotation of the cam lie in a vertical plane and at an angle a to the horizontal plane AA of movement of the carriage 6, said angle being slightly less than 0, which is one-half the cone angle. By this means when the cams, which are arranged so that the peaks of the profile of one are in line with the troughs of the other, are rotated no interference occurs between the peaks and troughs. Because of the angular placement of the cams 1 and 2, the common shaft 3 is either of the flexible type or arranged in several pieces connected by a flexible coupling or universal joint. The yarn 23 is guided to the traverse cams by way of guide 24 mounted on a plate 25. Plate 25 has edges 26, turned up to restrict sideways movement of the yarn and also serves to keep broken thread from entanglement with the shaft 3. For clarity the yarn 23 and the above described guiding members 24-26 are not shown in FIG- URE 1. A wind-up bobbin 27 is shown with part of a yarn package 28 built up on it. In operation the yarn 23 is lead to the windup bobbin by way of the primary traverse mechanism wherein it is traversed back and forth by alternately contacting the edges of the rotating cams 1 and 2 changing from contact with the peak of one cam to the trough of the other at each reversal of direction of movement of the yarn. The length of package Wound on the bobbin is governed by the depth of the trough of the cams measured from the peak and the distance between the primary traverse mechanism and the package. The yarn is laid on the bobbin by means of the secondary traverse mechanism in a number of equal stages which in the embodiment shown in FIGURE 1 is four. It is important that the length of the package wound at each stage should be exactly the same as the distance between stages so that there is no gap between or overlapping of adjacent layers. This condition is easily controlled for an increase in the speed of traverse increases the helix angle, causing a decrease in the actual length of package section produced. Thus the approximate length of each section is predetermined by the design of the cam profile and the distance between the package and the primary traverse mechanism but the exact width is controlled by fine adjustment of the speed of rotation of the cams.

This stepwise winding of the yarn on the bobbin to build up the full package length is obtained in the following way. Winding is started with the pin in one of the end spaces between the discs on the shaft and dwells there, as the yarn is being laid on the first section of the package. During this period the shaft 15 rotates until groove 12 coincides with the pin 10, the latter being then pushed by the piston rod 18 into the next space 11 wherein it dwells while the next section of the package is built up and so on until the full package length is built up. The groove 13 is cut on the opposite side and the groove 14 on the same side of the shaft 15 to the groove 12. Thus by this means the time required for one half revolution of shaft 15 is the dwell period of pin 10 in each of the two middle spaces and double this time i.e. the time for one complete revolution of shaft 15 is the dwell period for each end section of the package thereby allowing a uniform thickness of package to be built. Reversal of movement of the carriage 6 is obtained by means of the pin 21 which actuates the lever 19 just after the pin 10 has entered the adjacent space 11. The lever 21 operates valve 22 reversing the pressures in the double acting cylinder 17, thus providing the force required to move the pin 10 through the grooves 14, 13 and 12 in the reverse direction. The pin 10 does not immediately pass back through the slot 14, because rotation of the shaft 15 removes the slot 14 from the line of travel of the pin. It is generally convenient for each dwell period to be short for there is then no significant difference in diameter of the package after a section has been wound and thus no significant change in wind-up speed when the next section is commenced.

A typical pair of cam profiles is illustrated in FIG- URE 3. It is to be understood that the profiles form a pair in the sense that these are designed to rotate in the same direction and when oppositely placed to traverse the yarn from side to side. The major portion of each profile, as for example a-a or l1b, carries the yarn at substantially constant speed across the package surface while the portion immediately after a reversal, i.e. just after a trough or peak, is modified, as for example c-c or dd, to increase the speed of yarn traverse for a short distance to compensate for the very short yet finite time required for reversal of the yarn motion to take place. Without this compensation the yarn would be laid on the bobbin at the ends of the package, in a long curved path, producing a very weak foundation for the outer layers of yarn and the long loops of yarn at the package ends could become tangled and damaged.

The primary traverse mechanism of the present invention may be used as the sole means of traversing the yarn over the full length of the yarn package. A device somewhat similar, in principle to this has been described as one embodiment of the invention of British Patent No. 883,066. However, for traverse lengths of the usual order 6-8 inches, such units are very bulky and one particular advantage of the present device is that a compact unit operable at very high speeds is obtained.

Another problem encountered in high speed yarn winding, which the device of the present invention is especially suited to solve, is the problem of ribboning wherein a banded effect is produced in the wound bobbin by the laying of a number of layers of yarn one on top of the other at particular values of the ratio of thread guide reciprocation speed to wind-up speed: The values of this ratio which lead to ribboning alter as the size of the wound package increases. By means of the present invention ribboning, if it appears, is automatically minimised by the action of the secondary traverse in breaking up each traverse stroke into sections. Thus by the time when a particular section where ribboning has occurred is repeated the ratio will have altered slightly to a value at which ribboning does not recur.

What we claim is:

1. A traverse device for the high speed winding of yarns comprising: a primary traversing mechanism which includes two oppositely placed rotatable cams each formed from the frustum of a hollow cone and each having a profile comprising two peaks and two troughs, the axes of rotation of said cams being at an angle to a given plane and at an angle to each other, said angle with said given plane being slightly less than half the cone angle; a secondary traversing mechanism including a carriage bearing said primary mechanism; and means for moving said carriage to and fro along a straight line traverse path in said given plane in at least two steps in each direction along said straight line.

2. A traverse device for the high speed winding of yarns comprising: a carriage mounted for movement in a straight line in a given plane; means for reciprocating said carriage to and fro along the straight line in at least two steps in each direction along said straight line to determine a traverse path; and two opposed rotatable cams carried by said carriage on a common shaft, each of said cams being formed from the frustum of a hollow cone and each having a profile comprising two peaks and two troughs, the axes of rotation of said cams being disposed at an angle to each other and at an angle to said given plane which is slightly less than half the cone angle, said cams being arranged so that the peaks of the profile of one are in line with the troughs of the other, whereby no interference occurs between the peaks and troughs when said cams are rotated.

3. A traverse device according to claim 1 wherein the profiles of the cams are modified in the region immediately following a peak or a trough so as to temporarily increase the speed of yarn traverse immediately following a reversal of direction of yarn travel.

References Cited by the Examiner UNITED STATES PATENTS 1,928,365 9/1933 Anderson 24243.2 2,433,304 12/ 1947 Stream 242-43 2,611,548 9/1952 Heizer 24243 2,646,227 7/1953 Calhoun et al. 24243.2 2,736,506 2/1956 Selby 24243.2 3,004,726 10/1961 Kuppers 242-43.2 3,094,292 6/1963 Hebberling 242-43 3,109,602 11/1963 Smith 242 1'8 FOREIGN PATENTS 1,082,462 6/ 1954 France.

STANLEY N. GILREATH, Primary Examiner. 

1. A TRAVERSE DEVICE FOR THE HIGH SPEED WINDING OF YARNS COMPRISING: A PRIMARY TRAVERSING MECHANISM WHICH INCLUDES TWO OPPOSITELY PLACED ROTATABLE CAMS EACH FORMED FROM THE FRUSTUM OF A HOLLOW CONE AND EACH HAVING A PROFILE COMPRISING TWO PEAKS AND TWO TROUGHS, THE AXES OF ROTATION OF SAID CAMS BEING AT AN ANGLE TO A GIVEN PLANE AND AN ANGLE TO EACH OTHER, SAID ANGLE WITH SAID GIVEN PLANE BEING SLIGHTLY LESS THAN HALF THE CONE ANGLE; A SECONDARY TRAVERSING MECHANISM INCLUDING A CARRIAGE BEARING SAID PRIMARY MECHANISM; AND MEANS FOR MOVING SAID CARRIAGE TO AND FRO ALONG A STRAIGHT LINE TRAVERSE PATH IN SAID GIVEN PLANE IN AT LEAST TWO STEPS IN EACH DIRECTION ALONG SAID STRAIGHT LINE. 